Aphids, also known as plant lice, are minute plant-feeding insects that vary in size from 1-10 mm long.
Aphids are distributed world-wide, but they are most common in temperate zones. It is possible for aphids to migrate great distances (mainly through passive dispersal riding on winds) depending on the weather patterns. They have also been spread by human transportation of infested plant materials. When host plant quality becomes poor or is crowded, female aphids will produce winged offspring that can disperse to other food sources.
Aphids suck sap from soft leaf and stem tissue, causing the leaves to curl. Leaves are often able to outgrow the damage but sometimes become stunted and deformed. The honeydew often causes sooty mold to develop on infested plants. Aphids don't typically cause long term damage to trees. However, they can become a severe nuisance problem when infested trees are located over parking, picnicking, and other such areas where the honeydew falls onto vehicles, pavement, seats, etc.

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